boost::program_options config file option with multiple tokens

Question

I can not seem to be able to read from config file multitoken options like I can from command line. What is the syntax for the config file?

This is how the option descri

Answer 1

You can achieve the behavior you seek by writing a custom validator. This custom validator accepts :

./progname --coordinate 1 2
./progname --coordinate "1 2"
#In config file:
coordinate= 1 2

Here is the code:

struct coordinate {
  double x,y;
};

void validate(boost::any& v,
  const vector& values,
  coordinate*, int) {
  coordinate c;
  vector dvalues;
  for(vector::const_iterator it = values.begin();
    it != values.end();
    ++it) {
    stringstream ss(*it);
    copy(istream_iterator(ss), istream_iterator(),
      back_inserter(dvalues));
    if(!ss.eof()) {
      throw po::validation_error("Invalid coordinate specification");
    }
  }
  if(dvalues.size() != 2) {
    throw po::validation_error("Invalid coordinate specification");
  }
  c.x = dvalues[0];
  c.y = dvalues[1];
  v = c;
}
...
    po::options_description config("Configuration");
    config.add_options()
        ("coordinate",po::value()->multitoken(),"Coordinates (x,y)")
        ;

References:

• http://www.boost.org/doc/libs/1_46_1/doc/html/program_options/howto.html#id2219998
• https://stackoverflow.com/tags/boost-program-options/hot
• Handle complex options with Boost's program_options